do verification and extraction on memory, not files

Changes minzip and recovery's file signature verification to work on
memory regions, rather than files.

For packages which are regular files, install.cpp now mmap()s them
into memory and then passes the mapped memory to the verifier and to
the minzip library.

Support for files which are raw block maps (which will be used when we
have packages written to encrypted data partitions) is present but
largely untested so far.

Bug: 12188746
Change-Id: I12cc3e809834745a489dd9d4ceb558cbccdc3f71

11 files changed, 261 insertions, 209 deletions

diff --git a/Android.mk b/Android.mk
index c544db9..bd8d09b 100644
--- a/Android.mk
+++ b/Android.mk
@@ -98,6 +98,7 @@ LOCAL_SRC_FILES := \
 LOCAL_STATIC_LIBRARIES := \
     libmincrypt \
     libminui \
+    libminzip \
     libcutils \
     libstdc++ \
     libc
diff --git a/install.cpp b/install.cpp
index 980830c..0bd7945 100644
--- a/install.cpp
+++ b/install.cpp
@@ -186,12 +186,22 @@ really_install_package(const char *path, int* wipe_cache)
     ui->ShowProgress(VERIFICATION_PROGRESS_FRACTION, VERIFICATION_PROGRESS_TIME);
     LOGI("Update location: %s\n", path);
 
-    if (ensure_path_mounted(path) != 0) {
-        LOGE("Can't mount %s\n", path);
-        return INSTALL_CORRUPT;
+    // Map the update package into memory.
+    ui->Print("Opening update package...\n");
+
+    if (path) {
+        if (path[0] == '@') {
+            ensure_path_mounted(path+1);
+        } else {
+            ensure_path_mounted(path);
+        }
     }
 
-    ui->Print("Opening update package...\n");
+    MemMapping map;
+    if (sysMapFile(path, &map) != 0) {
+        LOGE("failed to map file\n");
+        return INSTALL_CORRUPT;
+    }
 
     int numKeys;
     Certificate* loadedKeys = load_keys(PUBLIC_KEYS_FILE, &numKeys);
@@ -204,27 +214,33 @@ really_install_package(const char *path, int* wipe_cache)
     ui->Print("Verifying update package...\n");
 
     int err;
-    err = verify_file(path, loadedKeys, numKeys);
+    err = verify_file(map.addr, map.length, loadedKeys, numKeys);
     free(loadedKeys);
     LOGI("verify_file returned %d\n", err);
     if (err != VERIFY_SUCCESS) {
         LOGE("signature verification failed\n");
+        sysReleaseMap(&map);
         return INSTALL_CORRUPT;
     }
 
     /* Try to open the package.
      */
     ZipArchive zip;
-    err = mzOpenZipArchive(path, &zip);
+    err = mzOpenZipArchive(map.addr, map.length, &zip);
     if (err != 0) {
         LOGE("Can't open %s\n(%s)\n", path, err != -1 ? strerror(err) : "bad");
+        sysReleaseMap(&map);
         return INSTALL_CORRUPT;
     }
 
     /* Verify and install the contents of the package.
      */
     ui->Print("Installing update...\n");
-    return try_update_binary(path, &zip, wipe_cache);
+    int result = try_update_binary(path, &zip, wipe_cache);
+
+    sysReleaseMap(&map);
+
+    return result;
 }
 
 int
diff --git a/minzip/SysUtil.c b/minzip/SysUtil.c
index e6f6506..2cfa39a 100644
--- a/minzip/SysUtil.c
+++ b/minzip/SysUtil.c
@@ -8,11 +8,14 @@
 #include <unistd.h>
 #include <string.h>
 #include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <limits.h>
 #include <errno.h>
 #include <assert.h>
 
-#define LOG_TAG "minzip"
+#define LOG_TAG "sysutil"
 #include "Log.h"
 #include "SysUtil.h"
 
@@ -46,13 +49,13 @@ static int getFileStartAndLength(int fd, off_t *start_, size_t *length_)
 }
 
 /*
- * Map a file (from fd's current offset) into a shared, read-only memory
+ * Map a file (from fd's current offset) into a private, read-only memory
  * segment.  The file offset must be a multiple of the page size.
  *
  * On success, returns 0 and fills out "pMap".  On failure, returns a nonzero
  * value and does not disturb "pMap".
  */
-int sysMapFileInShmem(int fd, MemMapping* pMap)
+static int sysMapFD(int fd, MemMapping* pMap)
 {
     off_t start;
     size_t length;
@@ -63,33 +66,146 @@ int sysMapFileInShmem(int fd, MemMapping* pMap)
     if (getFileStartAndLength(fd, &start, &length) < 0)
         return -1;
 
-    memPtr = mmap(NULL, length, PROT_READ, MAP_FILE | MAP_SHARED, fd, start);
+    memPtr = mmap(NULL, length, PROT_READ, MAP_PRIVATE, fd, start);
     if (memPtr == MAP_FAILED) {
-        LOGW("mmap(%d, R, FILE|SHARED, %d, %d) failed: %s\n", (int) length,
+        LOGW("mmap(%d, R, PRIVATE, %d, %d) failed: %s\n", (int) length,
             fd, (int) start, strerror(errno));
         return -1;
     }
 
-    pMap->baseAddr = pMap->addr = memPtr;
-    pMap->baseLength = pMap->length = length;
+    pMap->addr = memPtr;
+    pMap->length = length;
+    pMap->range_count = 1;
+    pMap->ranges = malloc(sizeof(MappedRange));
+    pMap->ranges[0].addr = memPtr;
+    pMap->ranges[0].length = length;
 
     return 0;
 }
 
+static int sysMapBlockFile(FILE* mapf, MemMapping* pMap)
+{
+    char block_dev[PATH_MAX+1];
+    size_t size;
+    unsigned int blksize;
+    unsigned int blocks;
+    unsigned int range_count;
+    unsigned int i;
+
+    if (fgets(block_dev, sizeof(block_dev), mapf) == NULL) {
+        LOGW("failed to read block device from header\n");
+        return -1;
+    }
+    for (i = 0; i < sizeof(block_dev); ++i) {
+        if (block_dev[i] == '\n') {
+            block_dev[i] = 0;
+            break;
+        }
+    }
+
+    if (fscanf(mapf, "%d %d\n%d\n", &size, &blksize, &range_count) != 3) {
+        LOGW("failed to parse block map header\n");
+        return -1;
+    }
+
+    blocks = ((size-1) / blksize) + 1;
+
+    pMap->range_count = range_count;
+    pMap->ranges = malloc(range_count * sizeof(MappedRange));
+    memset(pMap->ranges, 0, range_count * sizeof(MappedRange));
+
+    // Reserve enough contiguous address space for the whole file.
+    unsigned char* reserve;
+    reserve = mmap64(NULL, blocks * blksize, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
+    if (reserve == MAP_FAILED) {
+        LOGW("failed to reserve address space: %s\n", strerror(errno));
+        return -1;
+    }
+
+    pMap->ranges[range_count-1].addr = reserve;
+    pMap->ranges[range_count-1].length = blocks * blksize;
+
+    int fd = open(block_dev, O_RDONLY);
+    if (fd < 0) {
+        LOGW("failed to open block device %s: %s\n", block_dev, strerror(errno));
+        return -1;
+    }
+
+    unsigned char* next = reserve;
+    for (i = 0; i < range_count; ++i) {
+        int start, end;
+        if (fscanf(mapf, "%d %d\n", &start, &end) != 2) {
+            LOGW("failed to parse range %d in block map\n", i);
+            return -1;
+        }
+
+        void* addr = mmap64(next, (end-start)*blksize, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, ((off64_t)start)*blksize);
+        if (addr == MAP_FAILED) {
+            LOGW("failed to map block %d: %s\n", i, strerror(errno));
+            return -1;
+        }
+        pMap->ranges[i].addr = addr;
+        pMap->ranges[i].length = (end-start)*blksize;
+
+        next += pMap->ranges[i].length;
+    }
+
+    pMap->addr = reserve;
+    pMap->length = size;
+
+    return 0;
+}
+
+int sysMapFile(const char* fn, MemMapping* pMap)
+{
+    memset(pMap, 0, sizeof(*pMap));
+
+    if (fn && fn[0] == '@') {
+        // A map of blocks
+        FILE* mapf = fopen(fn+1, "r");
+        if (mapf == NULL) {
+            LOGV("Unable to open '%s': %s\n", fn+1, strerror(errno));
+            return -1;
+        }
+
+        if (sysMapBlockFile(mapf, pMap) != 0) {
+            LOGW("Map of '%s' failed\n", fn);
+            return -1;
+        }
+
+        fclose(mapf);
+    } else {
+        // This is a regular file.
+        int fd = open(fn, O_RDONLY, 0);
+        if (fd < 0) {
+            LOGE("Unable to open '%s': %s\n", fn, strerror(errno));
+            return -1;
+        }
+
+        if (sysMapFD(fd, pMap) != 0) {
+            LOGE("Map of '%s' failed\n", fn);
+            close(fd);
+            return -1;
+        }
+
+        close(fd);
+    }
+    return 0;
+}
+
 /*
  * Release a memory mapping.
  */
-void sysReleaseShmem(MemMapping* pMap)
+void sysReleaseMap(MemMapping* pMap)
 {
-    if (pMap->baseAddr == NULL && pMap->baseLength == 0)
-        return;
-
-    if (munmap(pMap->baseAddr, pMap->baseLength) < 0) {
-        LOGW("munmap(%p, %d) failed: %s\n",
-            pMap->baseAddr, (int)pMap->baseLength, strerror(errno));
-    } else {
-        LOGV("munmap(%p, %d) succeeded\n", pMap->baseAddr, pMap->baseLength);
-        pMap->baseAddr = NULL;
-        pMap->baseLength = 0;
+    int i;
+    for (i = 0; i < pMap->range_count; ++i) {
+        if (munmap(pMap->ranges[i].addr, pMap->ranges[i].length) < 0) {
+            LOGW("munmap(%p, %d) failed: %s\n",
+                 pMap->ranges[i].addr, (int)pMap->ranges[i].length, strerror(errno));
+        }
     }
+    free(pMap->ranges);
+    pMap->ranges = NULL;
+    pMap->range_count = 0;
 }
diff --git a/minzip/SysUtil.h b/minzip/SysUtil.h
index 55cd0e7..7adff1e 100644
--- a/minzip/SysUtil.h
+++ b/minzip/SysUtil.h
@@ -6,39 +6,47 @@
 #ifndef _MINZIP_SYSUTIL
 #define _MINZIP_SYSUTIL
 
-#include "inline_magic.h"
-
+#include <stdio.h>
 #include <sys/types.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct MappedRange {
+    void* addr;
+    size_t length;
+} MappedRange;
+
 /*
  * Use this to keep track of mapped segments.
  */
 typedef struct MemMapping {
-    void*   addr;           /* start of data */
-    size_t  length;         /* length of data */
+    unsigned char* addr;           /* start of data */
+    size_t         length;         /* length of data */
 
-    void*   baseAddr;       /* page-aligned base address */
-    size_t  baseLength;     /* length of mapping */
+    int            range_count;
+    MappedRange*   ranges;
 } MemMapping;
 
-/* copy a map */
-INLINE void sysCopyMap(MemMapping* dst, const MemMapping* src) {
-    *dst = *src;
-}
-
 /*
- * Map a file (from fd's current offset) into a shared,
- * read-only memory segment.
+ * Map a file into a private, read-only memory segment.  If 'fn'
+ * begins with an '@' character, it is a map of blocks to be mapped,
+ * otherwise it is treated as an ordinary file.
  *
  * On success, "pMap" is filled in, and zero is returned.
  */
-int sysMapFileInShmem(int fd, MemMapping* pMap);
+int sysMapFile(const char* fn, MemMapping* pMap);
 
 /*
  * Release the pages associated with a shared memory segment.
  *
  * This does not free "pMap"; it just releases the memory.
  */
-void sysReleaseShmem(MemMapping* pMap);
+void sysReleaseMap(MemMapping* pMap);
+
+#ifdef __cplusplus
+}
+#endif
 
 #endif /*_MINZIP_SYSUTIL*/
diff --git a/minzip/Zip.c b/minzip/Zip.c
index 439e5d9..6752bce 100644
--- a/minzip/Zip.c
+++ b/minzip/Zip.c
@@ -184,7 +184,7 @@ static int validFilename(const char *fileName, unsigned int fileNameLen)
  *
  * Returns "true" on success.
  */
-static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
+static bool parseZipArchive(ZipArchive* pArchive)
 {
     bool result = false;
     const unsigned char* ptr;
@@ -196,7 +196,7 @@ static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
      * signature for the first file (LOCSIG) or, if the archive doesn't
      * have any files in it, the end-of-central-directory signature (ENDSIG).
      */
-    val = get4LE(pMap->addr);
+    val = get4LE(pArchive->addr);
     if (val == ENDSIG) {
         LOGI("Found Zip archive, but it looks empty\n");
         goto bail;
@@ -209,14 +209,14 @@ static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
      * Find the EOCD.  We'll find it immediately unless they have a file
      * comment.
      */
-    ptr = pMap->addr + pMap->length - ENDHDR;
+    ptr = pArchive->addr + pArchive->length - ENDHDR;
 
-    while (ptr >= (const unsigned char*) pMap->addr) {
+    while (ptr >= (const unsigned char*) pArchive->addr) {
         if (*ptr == (ENDSIG & 0xff) && get4LE(ptr) == ENDSIG)
             break;
         ptr--;
     }
-    if (ptr < (const unsigned char*) pMap->addr) {
+    if (ptr < (const unsigned char*) pArchive->addr) {
         LOGI("Could not find end-of-central-directory in Zip\n");
         goto bail;
     }
@@ -230,9 +230,9 @@ static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
     cdOffset = get4LE(ptr + ENDOFF);
 
     LOGVV("numEntries=%d cdOffset=%d\n", numEntries, cdOffset);
-    if (numEntries == 0 || cdOffset >= pMap->length) {
+    if (numEntries == 0 || cdOffset >= pArchive->length) {
         LOGW("Invalid entries=%d offset=%d (len=%zd)\n",
-            numEntries, cdOffset, pMap->length);
+            numEntries, cdOffset, pArchive->length);
         goto bail;
     }
 
@@ -245,14 +245,14 @@ static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
     if (pArchive->pEntries == NULL || pArchive->pHash == NULL)
         goto bail;
 
-    ptr = pMap->addr + cdOffset;
+    ptr = pArchive->addr + cdOffset;
     for (i = 0; i < numEntries; i++) {
         ZipEntry* pEntry;
         unsigned int fileNameLen, extraLen, commentLen, localHdrOffset;
         const unsigned char* localHdr;
         const char *fileName;
 
-        if (ptr + CENHDR > (const unsigned char*)pMap->addr + pMap->length) {
+        if (ptr + CENHDR > (const unsigned char*)pArchive->addr + pArchive->length) {
             LOGW("Ran off the end (at %d)\n", i);
             goto bail;
         }
@@ -266,7 +266,7 @@ static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
         extraLen = get2LE(ptr + CENEXT);
         commentLen = get2LE(ptr + CENCOM);
         fileName = (const char*)ptr + CENHDR;
-        if (fileName + fileNameLen > (const char*)pMap->addr + pMap->length) {
+        if (fileName + fileNameLen > (const char*)pArchive->addr + pArchive->length) {
             LOGW("Filename ran off the end (at %d)\n", i);
             goto bail;
         }
@@ -352,15 +352,15 @@ static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
         }
         pEntry->externalFileAttributes = get4LE(ptr + CENATX);
 
-        // Perform pMap->addr + localHdrOffset, ensuring that it won't
+        // Perform pArchive->addr + localHdrOffset, ensuring that it won't
         // overflow. This is needed because localHdrOffset is untrusted.
-        if (!safe_add((uintptr_t *)&localHdr, (uintptr_t)pMap->addr,
+        if (!safe_add((uintptr_t *)&localHdr, (uintptr_t)pArchive->addr,
             (uintptr_t)localHdrOffset)) {
             LOGW("Integer overflow adding in parseZipArchive\n");
             goto bail;
         }
         if ((uintptr_t)localHdr + LOCHDR >
-            (uintptr_t)pMap->addr + pMap->length) {
+            (uintptr_t)pArchive->addr + pArchive->length) {
             LOGW("Bad offset to local header: %d (at %d)\n", localHdrOffset, i);
             goto bail;
         }
@@ -374,7 +374,7 @@ static bool parseZipArchive(ZipArchive* pArchive, const MemMapping* pMap)
             LOGW("Integer overflow adding in parseZipArchive\n");
             goto bail;
         }
-        if ((size_t)pEntry->offset + pEntry->compLen > pMap->length) {
+        if ((size_t)pEntry->offset + pEntry->compLen > pArchive->length) {
             LOGW("Data ran off the end (at %d)\n", i);
             goto bail;
         }
@@ -427,50 +427,30 @@ bail:
  *
  * On success, we fill out the contents of "pArchive".
  */
-int mzOpenZipArchive(const char* fileName, ZipArchive* pArchive)
+int mzOpenZipArchive(unsigned char* addr, size_t length, ZipArchive* pArchive)
 {
-    MemMapping map;
     int err;
 
-    LOGV("Opening archive '%s' %p\n", fileName, pArchive);
-
-    map.addr = NULL;
-    memset(pArchive, 0, sizeof(*pArchive));
-
-    pArchive->fd = open(fileName, O_RDONLY, 0);
-    if (pArchive->fd < 0) {
-        err = errno ? errno : -1;
-        LOGV("Unable to open '%s': %s\n", fileName, strerror(err));
-        goto bail;
-    }
-
-    if (sysMapFileInShmem(pArchive->fd, &map) != 0) {
-        err = -1;
-        LOGW("Map of '%s' failed\n", fileName);
-        goto bail;
-    }
-
-    if (map.length < ENDHDR) {
+    if (length < ENDHDR) {
         err = -1;
         LOGV("File '%s' too small to be zip (%zd)\n", fileName, map.length);
         goto bail;
     }
 
-    if (!parseZipArchive(pArchive, &map)) {
+    pArchive->addr = addr;
+    pArchive->length = length;
+
+    if (!parseZipArchive(pArchive)) {
         err = -1;
         LOGV("Parsing '%s' failed\n", fileName);
         goto bail;
     }
 
     err = 0;
-    sysCopyMap(&pArchive->map, &map);
-    map.addr = NULL;
 
 bail:
     if (err != 0)
         mzCloseZipArchive(pArchive);
-    if (map.addr != NULL)
-        sysReleaseShmem(&map);
     return err;
 }
 
@@ -483,16 +463,10 @@ void mzCloseZipArchive(ZipArchive* pArchive)
 {
     LOGV("Closing archive %p\n", pArchive);
 
-    if (pArchive->fd >= 0)
-        close(pArchive->fd);
-    if (pArchive->map.addr != NULL)
-        sysReleaseShmem(&pArchive->map);
-
     free(pArchive->pEntries);
 
     mzHashTableFree(pArchive->pHash);
 
-    pArchive->fd = -1;
     pArchive->pHash = NULL;
     pArchive->pEntries = NULL;
 }
@@ -528,29 +502,7 @@ static bool processStoredEntry(const ZipArchive *pArchive,
     const ZipEntry *pEntry, ProcessZipEntryContentsFunction processFunction,
     void *cookie)
 {
-    size_t bytesLeft = pEntry->compLen;
-    while (bytesLeft > 0) {
-        unsigned char buf[32 * 1024];
-        ssize_t n;
-        size_t count;
-        bool ret;
-
-        count = bytesLeft;
-        if (count > sizeof(buf)) {
-            count = sizeof(buf);
-        }
-        n = read(pArchive->fd, buf, count);
-        if (n < 0 || (size_t)n != count) {
-            LOGE("Can't read %zu bytes from zip file: %ld\n", count, n);
-            return false;
-        }
-        ret = processFunction(buf, n, cookie);
-        if (!ret) {
-            return false;
-        }
-        bytesLeft -= count;
-    }
-    return true;
+    return processFunction(pArchive->addr + pEntry->offset, pEntry->uncompLen, cookie);
 }
 
 static bool processDeflatedEntry(const ZipArchive *pArchive,
@@ -573,8 +525,8 @@ static bool processDeflatedEntry(const ZipArchive *pArchive,
     zstream.zalloc = Z_NULL;
     zstream.zfree = Z_NULL;
     zstream.opaque = Z_NULL;
-    zstream.next_in = NULL;
-    zstream.avail_in = 0;
+    zstream.next_in = pArchive->addr + pEntry->offset;
+    zstream.avail_in = pEntry->compLen;
     zstream.next_out = (Bytef*) procBuf;
     zstream.avail_out = sizeof(procBuf);
     zstream.data_type = Z_UNKNOWN;
@@ -598,25 +550,6 @@ static bool processDeflatedEntry(const ZipArchive *pArchive,
      * Loop while we have data.
      */
     do {
-        /* read as much as we can */
-        if (zstream.avail_in == 0) {
-            long getSize = (compRemaining > (long)sizeof(readBuf)) ?
-                        (long)sizeof(readBuf) : compRemaining;
-            LOGVV("+++ reading %ld bytes (%ld left)\n",
-                getSize, compRemaining);
-
-            int cc = read(pArchive->fd, readBuf, getSize);
-            if (cc != (int) getSize) {
-                LOGW("inflate read failed (%d vs %ld)\n", cc, getSize);
-                goto z_bail;
-            }
-
-            compRemaining -= getSize;
-
-            zstream.next_in = readBuf;
-            zstream.avail_in = getSize;
-        }
-
         /* uncompress the data */
         zerr = inflate(&zstream, Z_NO_FLUSH);
         if (zerr != Z_OK && zerr != Z_STREAM_END) {
@@ -676,12 +609,6 @@ bool mzProcessZipEntryContents(const ZipArchive *pArchive,
     bool ret = false;
     off_t oldOff;
 
-    /* save current offset */
-    oldOff = lseek(pArchive->fd, 0, SEEK_CUR);
-
-    /* Seek to the beginning of the entry's compressed data. */
-    lseek(pArchive->fd, pEntry->offset, SEEK_SET);
-
     switch (pEntry->compression) {
     case STORED:
         ret = processStoredEntry(pArchive, pEntry, processFunction, cookie);
@@ -695,8 +622,6 @@ bool mzProcessZipEntryContents(const ZipArchive *pArchive,
         break;
     }
 
-    /* restore file offset */
-    lseek(pArchive->fd, oldOff, SEEK_SET);
     return ret;
 }
 
diff --git a/minzip/Zip.h b/minzip/Zip.h
index c942828..05a2e60 100644
--- a/minzip/Zip.h
+++ b/minzip/Zip.h
@@ -46,11 +46,11 @@ typedef struct ZipEntry {
  * One Zip archive.  Treat as opaque.
  */
 typedef struct ZipArchive {
-    int         fd;
-    unsigned int numEntries;
-    ZipEntry*   pEntries;
-    HashTable*  pHash;          // maps file name to ZipEntry
-    MemMapping  map;
+    unsigned int   numEntries;
+    ZipEntry*      pEntries;
+    HashTable*     pHash;          // maps file name to ZipEntry
+    unsigned char* addr;
+    size_t         length;
 } ZipArchive;
 
 /*
@@ -68,7 +68,7 @@ typedef struct {
  * On success, returns 0 and populates "pArchive".  Returns nonzero errno
  * value on failure.
  */
-int mzOpenZipArchive(const char* fileName, ZipArchive* pArchive);
+int mzOpenZipArchive(unsigned char* addr, size_t length, ZipArchive* pArchive);
 
 /*
  * Close archive, releasing resources associated with it.
diff --git a/roots.cpp b/roots.cpp
index 47cea0b..28004a7 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -238,10 +238,16 @@ int setup_install_mounts() {
 
         if (strcmp(v->mount_point, "/tmp") == 0 ||
             strcmp(v->mount_point, "/cache") == 0) {
-            if (ensure_path_mounted(v->mount_point) != 0) return -1;
+            if (ensure_path_mounted(v->mount_point) != 0) {
+                LOGE("failed to mount %s\n", v->mount_point);
+                return -1;
+            }
 
         } else {
-            if (ensure_path_unmounted(v->mount_point) != 0) return -1;
+            if (ensure_path_unmounted(v->mount_point) != 0) {
+                LOGE("failed to unmount %s\n", v->mount_point);
+                return -1;
+            }
         }
     }
     return 0;
diff --git a/updater/updater.c b/updater/updater.c
index c7009fe..4e1cc9c 100644
--- a/updater/updater.c
+++ b/updater/updater.c
@@ -22,6 +22,7 @@
 #include "updater.h"
 #include "install.h"
 #include "minzip/Zip.h"
+#include "minzip/SysUtil.h"
 
 // Generated by the makefile, this function defines the
 // RegisterDeviceExtensions() function, which calls all the
@@ -65,19 +66,24 @@ int main(int argc, char** argv) {
 
     // Extract the script from the package.
 
-    char* package_data = argv[3];
+    const char* package_filename = argv[3];
+    MemMapping map;
+    if (sysMapFile(package_filename, &map) != 0) {
+        printf("failed to map package %s\n", argv[3]);
+        return 3;
+    }
     ZipArchive za;
     int err;
-    err = mzOpenZipArchive(package_data, &za);
+    err = mzOpenZipArchive(map.addr, map.length, &za);
     if (err != 0) {
         printf("failed to open package %s: %s\n",
-                package_data, strerror(err));
+               argv[3], strerror(err));
         return 3;
     }
 
     const ZipEntry* script_entry = mzFindZipEntry(&za, SCRIPT_NAME);
     if (script_entry == NULL) {
-        printf("failed to find %s in %s\n", SCRIPT_NAME, package_data);
+        printf("failed to find %s in %s\n", SCRIPT_NAME, package_filename);
         return 4;
     }
 
@@ -152,6 +158,7 @@ int main(int argc, char** argv) {
     if (updater_info.package_zip) {
         mzCloseZipArchive(updater_info.package_zip);
     }
+    sysReleaseMap(&map);
     free(script);
 
     return 0;
diff --git a/verifier.cpp b/verifier.cpp
index 0930fbd..55d58ee 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -111,15 +111,10 @@ static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_d
 // Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered
 // or no key matches the signature).
 
-int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys) {
+int verify_file(unsigned char* addr, size_t length,
+                const Certificate* pKeys, unsigned int numKeys) {
     ui->SetProgress(0.0);
 
-    FILE* f = fopen(path, "rb");
-    if (f == NULL) {
-        LOGE("failed to open %s (%s)\n", path, strerror(errno));
-        return VERIFY_FAILURE;
-    }
-
     // An archive with a whole-file signature will end in six bytes:
     //
     //   (2-byte signature start) $ff $ff (2-byte comment size)
@@ -131,22 +126,15 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
 
 #define FOOTER_SIZE 6
 
-    if (fseek(f, -FOOTER_SIZE, SEEK_END) != 0) {
-        LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
-        fclose(f);
+    if (length < FOOTER_SIZE) {
+        LOGE("not big enough to contain footer\n");
         return VERIFY_FAILURE;
     }
 
-    unsigned char footer[FOOTER_SIZE];
-    if (fread(footer, 1, FOOTER_SIZE, f) != FOOTER_SIZE) {
-        LOGE("failed to read footer from %s (%s)\n", path, strerror(errno));
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
+    unsigned char* footer = addr + length - FOOTER_SIZE;
 
     if (footer[2] != 0xff || footer[3] != 0xff) {
         LOGE("footer is wrong\n");
-        fclose(f);
         return VERIFY_FAILURE;
     }
 
@@ -157,7 +145,6 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
 
     if (signature_start <= FOOTER_SIZE) {
         LOGE("Signature start is in the footer");
-        fclose(f);
         return VERIFY_FAILURE;
     }
 
@@ -167,9 +154,8 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     // comment length.
     size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
 
-    if (fseek(f, -eocd_size, SEEK_END) != 0) {
-        LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
-        fclose(f);
+    if (length < eocd_size) {
+        LOGE("not big enough to contain EOCD\n");
         return VERIFY_FAILURE;
     }
 
@@ -177,26 +163,15 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     // This is everything except the signature data and length, which
     // includes all of the EOCD except for the comment length field (2
     // bytes) and the comment data.
-    size_t signed_len = ftell(f) + EOCD_HEADER_SIZE - 2;
+    size_t signed_len = length - eocd_size + EOCD_HEADER_SIZE - 2;
 
-    unsigned char* eocd = (unsigned char*)malloc(eocd_size);
-    if (eocd == NULL) {
-        LOGE("malloc for EOCD record failed\n");
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
-    if (fread(eocd, 1, eocd_size, f) != eocd_size) {
-        LOGE("failed to read eocd from %s (%s)\n", path, strerror(errno));
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
+    unsigned char* eocd = addr + length - eocd_size;
 
     // If this is really is the EOCD record, it will begin with the
     // magic number $50 $4b $05 $06.
     if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
         eocd[2] != 0x05 || eocd[3] != 0x06) {
         LOGE("signature length doesn't match EOCD marker\n");
-        fclose(f);
         return VERIFY_FAILURE;
     }
 
@@ -209,7 +184,6 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
             // which could be exploitable.  Fail verification if
             // this sequence occurs anywhere after the real one.
             LOGE("EOCD marker occurs after start of EOCD\n");
-            fclose(f);
             return VERIFY_FAILURE;
         }
     }
@@ -229,35 +203,23 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     SHA256_CTX sha256_ctx;
     SHA_init(&sha1_ctx);
     SHA256_init(&sha256_ctx);
-    unsigned char* buffer = (unsigned char*)malloc(BUFFER_SIZE);
-    if (buffer == NULL) {
-        LOGE("failed to alloc memory for sha1 buffer\n");
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
 
     double frac = -1.0;
     size_t so_far = 0;
-    fseek(f, 0, SEEK_SET);
     while (so_far < signed_len) {
-        size_t size = BUFFER_SIZE;
-        if (signed_len - so_far < size) size = signed_len - so_far;
-        if (fread(buffer, 1, size, f) != size) {
-            LOGE("failed to read data from %s (%s)\n", path, strerror(errno));
-            fclose(f);
-            return VERIFY_FAILURE;
-        }
-        if (need_sha1) SHA_update(&sha1_ctx, buffer, size);
-        if (need_sha256) SHA256_update(&sha256_ctx, buffer, size);
+        size_t size = signed_len - so_far;
+        if (size > BUFFER_SIZE) size = BUFFER_SIZE;
+
+        if (need_sha1) SHA_update(&sha1_ctx, addr + so_far, size);
+        if (need_sha256) SHA256_update(&sha256_ctx, addr + so_far, size);
         so_far += size;
+
         double f = so_far / (double)signed_len;
         if (f > frac + 0.02 || size == so_far) {
             ui->SetProgress(f);
             frac = f;
         }
     }
-    fclose(f);
-    free(buffer);
 
     const uint8_t* sha1 = SHA_final(&sha1_ctx);
     const uint8_t* sha256 = SHA256_final(&sha256_ctx);
@@ -269,10 +231,8 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     if (!read_pkcs7(eocd + eocd_size - signature_start, signature_size, &sig_der,
             &sig_der_length)) {
         LOGE("Could not find signature DER block\n");
-        free(eocd);
         return VERIFY_FAILURE;
     }
-    free(eocd);
 
     /*
      * Check to make sure at least one of the keys matches the signature. Since
diff --git a/verifier.h b/verifier.h
index 023d3bf..15f8d98 100644
--- a/verifier.h
+++ b/verifier.h
@@ -37,10 +37,13 @@ typedef struct {
     ECPublicKey* ec;
 } Certificate;
 
-/* Look in the file for a signature footer, and verify that it
- * matches one of the given keys.  Return one of the constants below.
+/* addr and length define a an update package file that has been
+ * loaded (or mmap'ed, or whatever) into memory.  Verify that the file
+ * is signed and the signature matches one of the given keys.  Return
+ * one of the constants below.
  */
-int verify_file(const char* path, const Certificate *pKeys, unsigned int numKeys);
+int verify_file(unsigned char* addr, size_t length,
+                const Certificate *pKeys, unsigned int numKeys);
 
 Certificate* load_keys(const char* filename, int* numKeys);
 
diff --git a/verifier_test.cpp b/verifier_test.cpp
index 88fcad4..10a5dda 100644
--- a/verifier_test.cpp
+++ b/verifier_test.cpp
@@ -17,12 +17,16 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 
 #include "common.h"
 #include "verifier.h"
 #include "ui.h"
 #include "mincrypt/sha.h"
 #include "mincrypt/sha256.h"
+#include "minzip/SysUtil.h"
 
 // This is build/target/product/security/testkey.x509.pem after being
 // dumped out by dumpkey.jar.
@@ -227,7 +231,13 @@ int main(int argc, char **argv) {
 
     ui = new FakeUI();
 
-    int result = verify_file(argv[argn], certs, num_keys);
+    MemMapping map;
+    if (sysMapFile(argv[argn], &map) != 0) {
+        fprintf(stderr, "failed to mmap %s: %s\n", argv[argn], strerror(errno));
+        return 4;
+    }
+
+    int result = verify_file(map.addr, map.length, certs, num_keys);
     if (result == VERIFY_SUCCESS) {
         printf("VERIFIED\n");
         return 0;